It is conventional, as known from Thomas Lauterbach and Matthias Unbehaun, Multimedia Environments for Mobiles (Memo): Interactive Multimedia Services for Portable and Mobile Terminals, Proceedings ACTS Mobile Summit 97, Aalborg, pp. 581 through 586, October 1997, to implement a combination of GSM (Global System for Mobile Communications) with DAB (Digital Audio Broadcasting). The aim is to use the low-rate GSM for a request channel, while the higher-rate DAB is utilized to make the requested data available. The intent is thereby to make possible so-called client-server applications in a motor vehicle. Both radio transmission systems (GSM and DAB) must be present, and a fixed allocation exists for the channels.
U.S. Pat. No. 5,854,985 describes a circuit that is arranged, for example, in a mobile telephone or another terminal, that performs an optimization of the radio connections for the user on the basis of defined criteria.